Returns the administrative actions taken ON this tenant — the platform-operator
changes a tenant could not previously see, filed under the tenant they act on.

Which planes are visible is the deployment's decision, not the caller's. On a
customer-operated deployment (private cloud, on premise) the operator is the
customer's own staff, so both planes are returned. On SaaS, PLATFORM-plane rows
are withheld. The optional actorPlane parameter can only NARROW that set — it
can never widen it, so requesting PLATFORM on SaaS returns an empty page rather
than an error or a disclosure.